Exploring multi-programming-language commits and their impacts on software quality: An empirical study on Apache projects

Modern software systems (e.g., Apache Spark) are usually written in multiple (PLs). There is little understanding on the phenomenon of multi-programming-language commits (MPLCs), which involve modified source files written in multiple PLs.This work aims to explore MPLCs and their impacts on development difficulty and software quality.We performed an empirical study on eighteen non-trivial Apache projects with 197,566 commits.: (1) the most commonly used PL combination consists of all the four PLs, i.e., C/C++, Java, JavaScript, and Python; (2) 9% of the commits from all the projects are MPLCs, and the proportion of MPLCs in 83% of the projects goes to a relatively stable level; (3) more than 90% of the MPLCs from all the projects involve source files in two PLs; (4) the change complexity of MPLCs is significantly higher than that of non-MPLCs; (5) issues fixed in MPLCs take significantly longer to be resolved than issues fixed in non-MPLCs in 89% of the projects; (6) MPLCs do not show significant effects on issue reopen; (7) source files undergoing MPLCs tend to be more bug-prone; and (8) MPLCs introduce more bugs than non-MPLCs.MPLCs are related to increased development difficulty and decreased software quality.